The present invention relates generally to the field of radar and more specifically to radar imaging apparatus and techniques. Synthetic aperture radar (SAR) ground mapping has been developed and used quite effectively for many years to produce high resolution ground maps. In general, this is accomplished by using the aircraft motion to synthetically produce a large effective antenna aperture in cross-range by coherently integrating the signal return. All relative motion between the SAR platform and target must be eliminated or compensated except for the straight line target flight path. The SAR thus requires complex target motion compensation and is unable to image well on a moving target. A variation of this technique is called Inverse Synthetic Aperture Radar (ISAR), and it can be used to image targets in motion. The radar may be moving or stationary and radar to target motion provides the cross-range image dimension. Individual scatterers on the target are resolved in slant-range by use of relatively large bandwidth waveforms and in cross-range by coherent integration of the signal returns. ISAR has been demonstrated using coherent high range resolution radar against ships and against space objects and air targets. Unfortunately, there are very few operational radars existing or planned for development which possess adequate instantaneous bandwidth to achieve the required range resolution. Further, the required sampling rates are extremely high. Range resolution is now limited by available analog to digital conversion speeds.